1. Avascular Necrosis: Causes and Treatment Coleman D. Fowble, M.D. Midlands Orthopaedics, P.A. Columbia, SC

2. Introduction Definition Loss of blood flow to the bone leading to death of the cellular components of bone.

3. Avascular Necrosis AVN Osteonecrosis Aseptic necrosis Ischemic necrosis Bone infarction

4. Bones Affected Femoral head – most common by far Shoulder – humeral head Odontoid (Neck) Scaphoid (Wrist) Lunate (Wrist) Talus (Ankle)

5. Examples

6. Treatment Frustrating Staging very subjective in lower stages

7. Etiologies Trauma Alcohol Steroids Diving (Caisson’s Disease) Sickle Cell Idiopathic (up to 30% of cases)

8. Symptoms Pain Decreased range of motion

9. Risk Factors Alcoholism Pancreatitis Diabetes Gout

10. Staging Initially radiographic staging Revised with advancement of MRI

11. Classification Ficat Original x-ray classification of hip Other classifications exist for talus, scaphoid, etc.

12. Stage 0 No clinical symptoms No radiographic abnormalities Microscopic diagnosis

13. Stage I May or may not have symptoms Radiographs and CT are normal MRI is abnormal as is bone scan Microscopic exam confirms diagnosis

14. Stage II Patient is symptomatic X-rays show osteopenia, sclerosis, cysts No subchondral lucency or collapse MRI confirms diagnosis

15. Stage III X-rays show subchondral lucency and collapse Crescent sign Shape of femoral head is preserved Subclassified by extent of crescent IIIa 15% of head IIIb 15-30% of ahead IIIc greater than 30%

16. Stage IV Flattening or collapse of head on x-ray Loss of joint space Subclassified by extent of collapse like Stage III IVa IVb IVc

17. MRI Stage IV

18. Stage V Arthritic changes evident on x-rays with loss of joint space and spurring May affect acetabular side of the joint

19. Stage V

20. Stage VI Extensive destruction of femoral head and joint May be indistinguishable from osteoarthritis

21. Treatment Options Stage dependent Clinical signs and symptoms Physiologic condition Age Medical comorbidities

22. Observation Normal x-ray Possible abnormal MRI No clinical signs or symptoms

23. Core Decompression Stage I or II With or without hardware Age

24. Core Decompression Added fixation

25. Free Vascularized Fibular Graft Pioneered in 1979 by Dr. Urbaniak at Duke Over 2500 performed Multidisciplinary approach Only center with real consistent results

26. Core Decompression Vascularized fibular graft

27. Partial Resurfacing No Longer in favor Disastrous results Loosening Fracture Migration of implant

28. Hip Replacement Too much destruction of head Age

29. Hip Resurfacing Age Bone preserving More functional hip replacement

30. Total Hip Versus Resurfacing

31. Workman's Compensation Trauma Secondary injury Difficult May take several years to show up

32. Femoral Neck Fracture Basilar neck Transcervical Subcapital Intertrochanteric

33. Femoral Neck Fracture Location of fracture determines risk of AVN

34. Treatment Examples Fracture pattern determines treatment Other factors Age Comorbidities

35. Transcervical Fracture

36. Fixation 3 Screws Screw and sideplate Intramedullary device

37. AVN After Treatment AVN can occur long after treatment

38. Replacement Hemiarthroplasty Total hip

39. Summary AVN is the disruption of the blood supply to bone There are multiple causes Diagnosis may be delayed Treatment is dependent on stage and other factors

40. Sources Staging of Avascular Necrosis. Orthopaedia Main. In: Orthopaedia-Collaborative Orthopaedic Knowledgebase JBJS Br. Core Decompression of the Distal Femur. Vol. 71-B. August, 1989 JBJS. Treatment of Osteonecrosis with Free Vascularized Fibular Graft. Vol 77. 1995